The synthesis of cytochromes aa3 plus b is neurohormonally regulated in fat body mitochondria of Blaberus discoidalis cockroaches and occurs during fat body maturation in recently-emerged adults. The neurohormone increases the energy-generating capability of the fat body and its capacity for biosynthetic activity. Indirectly this influences other physiological processes within the insect that rely on the fat body for biosynthetic products. The research will isolate and structurally characterize the neurohormone and investigate the timing of neurosecretion. Studies will be performed on specific cytochromes to identify the action of the neurohormone on cytochrome synthesis at the cellular level. The physiological significance for increasing the energy-generating capacity of the fat body is examined in terms of its impact on the previtellogenic maturation of the tissue and the rate of egg generation.